Oxytetracycline hydrochloride (OxyCl-I) was purchased from Todo Droga (Córdoba, Argentina). β-cyclodextrin (β-CD, MW = 1135) was kindly provided by Ferromet (agent in Argentina of Roquette (France)). L-aspartic acid (ASP) was provided by Anedra (Buenos Aires, Argentina), N-acetylcysteine (NAC) and Histidine (HIS) were purchased from Sigma-Aldrich (Milwaukee, WI, USA). All chemicals were of an analytical grade. Isopropyl alcohol and phosphoric acid were provided by Cicarelli (Santa Fe, Argentina). Ethanol was purchased from Sintorgan (Buenos Aires, Argentina). Acetonitrile J.T.Baker was supplied by Avantor Performance Materials (Xalostoc, México). Deuterium oxide (D2O) was provided by Sigma-Aldrich (Saint Louis, MO, USA).
A spectrophotometer, Cary 60 UV-Vis (Agilent Technologies, Santa Clara, CA, USA), with 10 mm of quartz cells was used for all spectral measurements.
The HPLC system consisted of an Agilent 1100 series pump, an autosampler, a multiple-wavelength ultraviolet-visible (UV-vis) detector, and Chemstation software Rev. B 04.03 (Agilent Technologies, Waldbronn, Germany).
A spectrophotometer, Cary 60 UV-Vis (Agilent Technologies, Santa Clara, CA, USA), with 10 mm of quartz cells was used for all spectral measurements.
The HPLC system consisted of an Agilent 1100 series pump, an autosampler, a multiple-wavelength ultraviolet-visible (UV-vis) detector, and Chemstation software Rev. B 04.03 (Agilent Technologies, Waldbronn, Germany).